1. Field of the Invention
The invention relates to a device for calibrating and testing ring-shaped current clamps, comprising a calibration housing with an outer conductor enclosing the current clamp and an inner conductor passing through the current clamp.
2. Discussion of Background
Current clamps can be divided into measuring clamps and current injection clamps. Measuring clamps act as current transformers and current injection clamps as transformer with a secondary winding. They are mainly used in the fields of EMC, EMP, lightning testing, ESD and EMI control.
Current clamps are very sensitive to overloading. The inbuilt terminating resistors can be easily destroyed or, worse, damaged if the currents are too high. Damaged resistors cannot be easily detected and may falsify the measurements unnoticed.
From the point of view of quality control, it is therefore important to be able to measure the frequency response of such current clamps. For these purposes, the firm EATON CORPORATION, 5340 Alla Road, Los Angeles CA 90066, for example, offers a so-called calibration jig. This device essentially consists of an open housing and an inner conductor which is enclosed by the current clamp during testing. However, measurements have shown that this test device is unusable for higher frequencies from several hundred MHz to 1 GHz.